Process for the purification and separation of gas mixtures



Dec. 8, 1953 H, KAHLE 2,661,808

PROCESS FOR THE PURIFICATION IND SEPARATION OF GAS MIXTURES, Filed Oct.10 1950 2 Sheets-Sheet l Fig.1

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' PURIFIOAT PRO S FOR THE AND ARATION OF GAS MIXT S Filed Oct. 10, 1950.2 Sheets-Sheet 2 of the adsorber which is located adjacent to thecooler is not deloaded. Therefore, it is practically only the loading oradsorbing section located in the center portion of the adsorber, whichis subjected to adsorption and desorption actions. In

this manner, the regenerative gas and the heat H applied during theregenerative period, as well as the cold applied during the loadingperiod, are utilized in a very economical manner.

A manner of carrying out the invention is illus- Two adsorbers, oradsorber branches, A and B are provided. Layers {of an adsorbentmaterial are indicated at I, I I; these layersare connected in parallelwith the cooling spirals 4, IE; cold regenerator end portions 2, I2 arelocated at the one side and heaters 5, I5, as well as heat regeneratorend portions 3, I3 at the other side of the adsorbers. Change-overdevice or valve 8 serves to shift the flow of the fresh gas and of theloaded regenerative gas and a changeover device or valve 9 shifts theflow of the residual and of the fresh regenerative gas. Heating iseffected in the heaters 5, I by steam or electricity. 7 V

In accordance with another embodiment of the invention, the heating-andcooling may be combined in such a manner that a cold medium iscyclically heated and cooled by being conducted through a system whichconsists of compressor 6, liquefier 5 or I5, expansion valve I,

evaporator 4 or I4. The liquefiers 5, I5 serve as a heating source, theevaporators 4, I4 as a cooling source.

The gas purification'or separation is performed in the above describedapparatus in the following manner.

The fresh gas enters at It, passes through change-over device 8 andenters, for loading purposes, through tube I6 into the left sideadsorber A; it passes through the regenerator 2, which was blown ccldinthe preceding period, adjacent cooler 4, the adsorbent layer I, heater.5, heat regenerator 3,'and is discharged through tube I9, change-overdevice 9 and tube 2 I. Simultaneously, regenerative gas passes from tube20, through change-over device 9, tube Il, heat regenerator I 3, heaterI5, adsorbent layer II, cooler I4, the regenerator I2, tube I8,change-over device 8 and is discharged through tube 22.

The approximate temperature of a gas particle during the commencement ofthe charging or loading period is illustrated in the schematic Fig. 2,by the line Iii-49, the temperature of a regenerative gas particle atthe start of the rinsing action by line III8; the dotted line passingbetween the lines I6l9 and I'II8 indicates the temperature in theadsorbent and in the storage material. During the cooling period of thegas, the dotted line passes below and during the heating period abovethe gas temperature indicating line. The'temperature change in 0 C. isapparent from the temperature scale on the left hand side of Fig. 2. I

The horizontal line indicates the length of the adsorber from point I6to I9 and from point l8 to point IT, respectively. The non-bracketednumbers refer to the .fresh gas and the residue gas, the bracketednumbers to the regenerative gas.

It appears from Fig. 2 that the temperature of a gas particle, asindicated by the arrow I6 is first lowered in the regenerator 2 andhereupon in the cooler 4; in the adsorbent layer I the temperature israised and this raise continues in heater 5. The temperature then drops.

A regenerative gas particle passing, as indicated by arrow I1, into thesecond adsorber B in an opposite-direction to the before described gasflow is first heated in accumulator i3, the

' room temperature.

heating is continued in heater I5; however, in the adsorbent layer I I adrop of the temperature occurs which is continued in cooler l4;hereafter,

the temperature rises again to a few degrees above The dotted lineindicating the "temperature of the storage and adsorbent material in theadsorber passes between lines I6--I9 and III8.

It will thus be seen from Fig. 2 of the drawing that the temperature ateach point in the how path through the apparatus remains approximatelyconstant during both the adsorbing and regenerating phases of the cycle.By the phrase approximately constant as used in this specification andthe claims, it is meant that each point of the apparatus will have atemperature indicated approximately by the dashed line in Fig. 2, thistemperature remaining between the 'limits set by the two solid lineswhich indicate the temperature of the gaseous mixture and theregenerative gas respectively. That is, the temperature of the apparatuswill deviate from the dashed line toward either of the solid lines,.butthis deviation will be slight and the temperature of the apparatus willnever attain that of the gases indicated by the solid lines.

The operation of the method is diiierent in conformity with itsdifferent objects.

If a purification of the gas is intended and a recovery of theimpurities is not desired, the

rinsing may be efiected with any type of regenerative gas. To useincreased pressure during the charging or loading period may not benecessary;

however, it is recommended, if the gas is to be used further underpressure. If the gas is further separated and products of the separationare obtained, which are not to be utilized, they may be employed for therinsing of the container which is to be discharged.

I A recovery of the adsorptive components may be attained by intensivelytreating a restricted quantity of the regenerative gas and enriching, inthis manner, the adsorbates which were removed during heating andregenerating in a small volume of the sluicing gas.

The enriched regenerative gas may be further enriched or separated inany customary. manner, for instance, by fractional condensation and by afurther adsorption. When using intensive. cooling, it is quite possibleto enrich the'componentsv to such an extent, that they alreadycondense'in the cooling device; from there, they may be dischargedcontinuouslyfor which purpose suitable collecting vessels should beprovided in the vicinity of the point where thecondensates form.

' An apparatus for carrying out the modified process of the invention asdescribed hereinabove is illustrated in Fig. 3. The two adsorberbranches are again each provided with layers of adsorbent material 3iand 4!. The cold accumulators 32, 42 are disposed at one end and theheat accumulators 33, 43 at the other end of each adsorber branch. Thecooling devices 34,44 are the valves g1, 2,8.

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, i e theestehiee iic t assastiye emnenstts s heated-tee estates t is aiarsesi ht ge re aes um; 3; when. ts: u tare. s: aise he methane; eras ethis s a 41 h eaten-Lessee Ait telyew hesei h e e h i e eieadspi'heteslt eate e he s t a a d lireue t heteeeeesi r cond it c attestQt mas-be s he fi st aqeesbe sta ternate he in. t e eesmaibef dth etshalve M0 he cooling-demote 3 4,: and; Q4, respectively, is deflected bythe deflectors and 26 and is collected by the collections; 2.8.; and:31]; and may; be obtained'frhm 7 oo m' The te. th h htee pt a ed es ates te tis en-v .Miti a ee s m the tie s eet-teatime eaaai Since certainchanges in carrying out the a b gve process could be made withoutdeparting irornthe eeps t m it is a s; hat al tttrte ttaj i ied in theabove description or showrrjint h e accompanying drawings shall beinterpreted as illustrative and not in a'l-i 'ng sense. f o Having thusdescribed theinve'ntion, what I laim as tee and desire tdte' see-e ittetiits Pate nt is as follows: f T f 1. An adsorption apparatuscomprising a pair of adsorbing means each containing an adsorbent pipeeither material and adapted to hav gases flow th of said pair of heataccumulator means which through, a h f aid t adsorbing means h are incommunication with said heating means ing at ne end there f a d i floommuniom and to connect the other of said last-recited pair tiontherewith a heating means, a first pair of of heat accumulator means tosaid gas mixture heat accumulator means each in communication 00 OutletP p the temperature of e ch of the heat with a respective one of saidheating means d accumulator means in communication with the forreceiving, storing and transferring heat to Cooling means fellingthroughout its w Path and from gases flowing therethrough, a pair of atan epproXimetely Constant gradient from the cooling means each incommunication ith a end connected to said first valve means towardspective one of the opposite ends of said adsorbing 5 the end incommunication with the cooling mea s means, a second pair of heataccumulator means Wh e h t p u is a its lowest D the each incommunication with a respective one of t p a u f a h f t ads rbi m ansrissaid cooling means, an inlet pipe for supplying t oug out i s fl w paat an pp to said apparatus a gaseous mixture containing y Constantgradient f Said IOWeSt p t ocomponents to be adsorbed therefrom, anoutlet wa d a i st mp ratur point at the end of pipe for delivering fromthe apparatus said gasthe adsorbing means in communication with the ecusmixture after the components have been adheating means, e p tu 0 each 0fthe sorbed therefrom, an inlet pipe for supplying adheat accumulatormeans in communication with sorbent-regenerating gas to said apparatus,an the heating means falling thr i fiOW outlet pipe for delivering fromthe apparatus said 76 p h at an approximately Constant g adient fromsaid highest temperature point at the end in' communication with theheating means, toward the end connected to said second valve means,whereby one of said adsorbing meansmay alternatively adsorb condensiblecomponents from the gaseous mixture or be regenerated whilesimultaneously the other adsorbing means is alternatively beingregenerated or adsorbing respectively, the temperatures and gradients ofeach adsorbing means and its associated heat accumulators remainingapproximately constant for both the adsorbing and regenerating phases ofthe cycle.

3. An adsorption apparatus comprising a pair of adsorbing means eachcontaining an adsorbent material and adapted to have gases flowtherethrough, each of said two adsorbing means having at one end thereofand in flow communication therewith a heating means, a first pair ofheat accumulator means each in communication with a respective one ofsaid heating means and for receiving, storing and transferring heat toand from gases flowing therethrough, a pair of cooling means each incommunication with a respective one of the opposite endsof saidadsorbing means, a second pair of heat accumulator means each incommunication with a respective one of said cooling means, an inlet pipefor supplying to said apparatus a gaseous mixture containing componentsto be adsorbed therefrom, an outlet pipe for delivering from theapparatus said gaseous mixture after the components have been adsorbedtherefrom, an inlet pipe for supplying adsorbent-regenerating gas tosaid apparatus, an outlet pipe for delivering from the apparatus saidadsorbent-regenerating gas after the latter has performed itsregenerat-ive function, a first valve means selectively operable toconnect to said gas mixture inlet pipe either of said heat accumulatormeans which are in communication with said cooling means and to connectthe other of said last-recited heat accumulator means to saidregenerating gas outlet pipe, and a second valve means selectivelyoperable to connect to said regenerating gas in-' let pipe either ofsaid pair of heat accumulator means which are in communication with saidheating means and to connect the other of said last-recited pair of heataccumulator means to said gas mixture outlet pipe, whereby one of saidadsorbing means may alternatively adsorb condensible components from thegaseous mixture or be regenerated while the other adsorbing meansalternatively is being regenerated or is adsorbing respectively, thetemperature at each point in the flow path through each of saidadsorbing means and heat accumulator means remaining approximatelyconstant for both the adsorbing and regenerating phases and a pair oflongitudinal hollow enclosures, each of said adsorbing means and itsassociated heat accumulator means and heating and cooling means beingenclosed within a respective one of said enclosures.

4. A process for the separation of adsorptive components from gaseousmixtures, said process comprising the steps of passing the gaseousmixture through a heat accumulator having a temperature lower than thegaseous mixture to cool the latter and transfer heat to saidaccumulator, passing the cooled gaseous mixture through a cooling meansto further cool the mixture, then passing thelatter through an adsorberto condense therein said adsorptive components and to heat said gaseousmixture thereby, then passing the uncondensed gas through a heatingmeans to further heat said uncondensed gas, then'passing the latterthrough a second heat accumulator to heat the said second accumulatorand to cool said uncondensed gas, then passing regenerative gas in adirection reversed with respect to the direction of flow of said gaseousmixture through said second heat accumulator so as to be heated thereby,then through said heating means to be further heated, then through saidadsorbing means to regenerate the latter and to cool said regenerativegas, and then through said firstrecited heat accumulator so as to coolthe latter, and then repeating the cycle of operation recited above, allthe aforementioned steps being carried out while maintaining thetemperature at each point in the flow path through each of saidadsorbing means and heat accumulators approximately constant for boththe adsorbing and regenerating phases of the cycle.

HEINRICH KAHLE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,548,280 Ray Aug. 4, 1925 1,616,242 Voress et al. Feb. 1,1927 1,934,075 Lewis Nov. 7, 1933 1,948,779 Abbott et al Feb. 27, 19341,959,389 Shoosmith May 22, 1934 2,083,732 Moore et a1 June 15, 19372,354,383 Kiess Kalt July 25, 1944 2,535,902 Dailey, Jr. Dec, 26, 19,50

